Telephone-repeater.



N. G. WARTH.

TELEPHONE REPEATER.

APPLICATION FILED DEO.14,1908.

960,45 Patented June 7,1910.

A z GUM/mea UNITED S arnnr earns.

NATHANIEL G. WARIH, F CQLUMBUEi, QHIG.

TELEPHONE-REPEATER.

Specification of Letters Patent.

Patented June a, ri id.

Application filed December 14, 1908. Serial No. 467,323.

To all whom it may concern: 1

Be it known that I, NATHANIEL G. \VARTH, a citizen of the United States, residing at Columbus, in the county of Franklin and State of Ohio, have. invented a certainnew and useful Improvement in Telefore been realized.

.owingto the very weak or exhausted charactor of the currents usually available in one direction, and frequently in both directions, at a repeater station, it has been requisite, in order to secure such results as have heretofore been attained, to make the mobile parts of repeaters, such as armatures, diaphragms and electrodes, ver'ysmall and of light weight, so that they should be capable of operation by ordinary speech or vocal currents; The superior efiicieney and strong transmitting quality of the well known Hunnings or granular type of transmitting instrument for ordinary telephone service has caused it to be adapted, in the form of the also 'well known White solid-back, button transmitter, as the best known instrument for repeating and reinforcing telephonic transmlssion. I have found that this instrument, even when constructed in the most delicate and perfect manner. for such service, and when used with a highly efficient-receiver, has such. mechanical resistance to actuation by the weak currents in thereceiver that the repeated currents are distorted in form, or character; that some waves are lost, betweenthe receiving element and the transmitting element, not beingu'eproduced when received, and that the amplitude of vibration is restricted,

correspondingly restricting the volume and power in reproduction, and decreasing the r'ange of j'transmisswn. The resistance to actuationofiered by theaforesaid form of transmitter is due mainly to the stressed and peripherally clamped andbounded diaing phragm of the carbon button, and the trouble is aggravated by the added stress of the diaphragm due to the pull of the sensitizing magnet,'which causes the diaphragm to reach practically its limit of movement in one, usually the forward, direction. This "resistance to motion is further increased by the inertia of the relatively heavy mass of matter carried by the diaphragm, embody: the vibratory armature and electrode, together with their means of attachment to the diaphra m. Were the operating cur rents of su 'cient strength toactuate this mechanism, reduced as it is toits racticable minimums of weight, and size, an increased to its maximum of practicable mobility, the transmitter would render very much improved results, both as to the quality and as to the volume of the reproduced currents.

By means of my present invention I am enabled to accomplish the results sought in'ah1ghly practical and efiicient manner. This I do mainly by the use of a double relay or repeater, one acting as an auxiliary to the other, adapting eachto its particular functions, and although somewhat complicating the repeater mechanism and operation, yet

justifying this step by the improved results.

and with their small additional cost. I emcar n transmitting re ater in a local repeating circuit, and uti ize the repeater in. a secondary capacity as a transmitting repeater or as the transmitter of the double arrangement. In this arrangement the sec ondary repeater is operated by its receiver element, or on its receiver side, by the reinforced current, from a main line repeater, thus utilizing a very efiicient receiving repeater provided with a verysensitive transmltter. The combination operates -ploy0the receiving element of the granular as follows: the sensitive receiving repeater, faithfully reproduces the telephonic waves received from the transmitting end of the line and transfers them by means of a local circuit arrangement to the more owerful transmitting repeater for reprouction and retransmission with reinforced power to the terminating or receiving end of the line. The receiver in such cases, operatm power of the attenuated line currents, cannot roduce a'sufficiently vigorous actuation of t e transmitnrnv to secure clear and strong retransmission, white with method the heavy service transmitter is actuated by too imperfectly and only with the comparatively stron local ci'iri'e1it,'wl1icl 1 current is very' near y a perfect fac-simile of the original current, and the resultant reinforced line current is very similar in form and in strength to the original transmission. The results obtained from-the ,use of the telepl iprnelepeater' indicate that serious attenuatlon of the' currents, in the line occurs before serious distortion, and-this condition works to advantage for long distancetrans mission by means 'ofthe repeater. Nero it possible to eliminate the difiicu'lty or; attenuated line currents the use of a repeater would be unnecessary, but as the use of a repeater appears the .best solution of extraordinarily long-distance transmission, and the cheapest solution of ordinary long-dis tance transmission, it will be a. great gain vtion with an illustration of the same in if the telephone repeater be made as efiicient and as satisfactoryin telephony as the telegraph repeater is in telegraphy.- As further means to. this end, I employ in the receiving element of each repeater, a polarized armature influenced by both the attractive and repulsive effects .due to the alternations of the telephoniccurrent in the receiving magnets or windings of the eceiving and the auxiliary relays for t e purpose of increasing the efficiency of said receiving elements.

I will now proceed to describe a particularexemplification of my invention in connecthe accompanying drawings. y

In said drawingsFigure- 1 is an illuss tration in side elevation, partly in section, of the repeater for receiving the weak'inward currents from the line, and for reproducing and reinforcing them for the auxiliary or transmitting local repeaterto re-repeat with re-reinforced current and effect to the out- I ward line. Fig. 2 is an illustration of my secondary or transmitting repeater, used forreinforcing the reinforced, quality ma ntained currents from the receiving line-repeater. Fig. 3 is a diagrammatieal illustration of.

' my double repeater, showingthe arrangement of apparatus and circuits for repeating in but one direction, that is, it represents but one side, or half, of'a reciprocal repeater of this invention. Fig. 4 is a diagrammatical' illustration of my. double repeater adapted to, or as used with,the form or ty e of twin repeater, shown in-my patent of t e United States No. 894,170; .of July 21st, 1908, and a modified arrangement in my pending application filed July'15th, 1907,

S. No. 383,883. This arrangement of the apparatus and circuits provides forreciprocal repeating, showing both hal'vesof a reciprocal repeater under the present invention and forming a twin double repeater giving unidirectional retransmission,

In Fig. 1 the character-B designates a base of insulating. material,- cir'cular in form,

' supporting the delicate rec eiving repeater R and the glass covering G for same. U1 des- 1gnates"tlie sensitizing permanent magnet receiving coil and. for polarizing the spring supported iron armature A, The magnet U is, by means of brass screws 1), b, mounted. upon the brass bracketl), A soft iron tube 23; driven, or screwed, into a perforation in the south or S pole of the permanent magnet, and also passingthrough a 'cor'-' responding perforation in' the brass bracket D, forms the'core, for the receiv-ing'coil C. An adjustable extension for this core is proin the core tube It, is rendered adjustable.toward or-away from the {polarized armature A; The end of this screw'bolt t is furnished with a very' small copper tip 1? to The coil O is placed upon the polar endof thetube ,t to cause it to vary the magnetic flux with its maximum effect; The opposite pole N, or north end, of the permanent ma get U is equipped with. means. for supporting, and for. regulating. the adjustment of the sensitive transmitter, said transmitter embracingthe platinum electrode 6' and the carbon button electrode 0. The platinum the-lower end of the light springer steel the support (Z between the bracket D and the N pole of themag'net U. This support is formed by three insulating blocks, as shown, bridgingthe space between the bracket and or screws f, passed through 'properscrew holes in the bracket and magnet, and also being provided with athreadcd hole for the fastening screw 9. The tongue a is elastic and can be adjusted by. means of its own tension and the set screw {passed through latin-g tip to prevent elcci'rical" contact or connection with-the steel tongue a, toavoid short cn'cmlingthc transmitter through the electrode ton ue a. An adjusting screw of iron 3 passed through the N poleof the vided in thes'crew bolt t ,which,by means of its exterior threads and the interior threads prevent the polarized. armature A from sticking to it if it. should contact therewithelectrode 0 and thearmature A are fixed upon the magnet, and is held in place by a screw extending through the insulating blocksmounted upon a brass back, saidmember,

and supported by'thc bracket D. Thisad justing screw i is provided with illldllSlI',

for creating an initial magnetic field for the tongue a, which is carried and insulated by bracket D and magnet Ui-with the platinum magnet U serves in the adjustment of the tongue at to provide a path for the magnetic flux to-more easily reach the steel tongue and through it the armature A to polarize the latter, An iron contact disk is attached to the tongue a at the point of contact with the iron screw 9' serves to improve the path of the ma netic flux to the armature.

The a'd ustme-nt of the parts should be tongue a. The armature A should. be held close'to, but out of contact with, the extension core P. The tongue (1 should be adjusted to lightly follow the vibrating platinum electrode, so as always to remain in contact therewith, It will be noted that the inertiaof'the tongue 1 plus the combined weight of the small armatnreand platinum contact is very small, and that the pushing tendency of the carbon electrode even reduces it, hence it is' very responsive to weak telephonic currents. The battery flow between theelectrodes can be very small because the work to be done in repeating to the transmitting repeater through the local circuits'is light; and further very little'heat is develo-ped'in the transmitter. The two steel tongues serve to lead the battery current to and from the electrodes, and connections are made with them for the purpose by a .the electrodes, prevented "from undergoingor setting up vibrations of their own. In

short they are damped and under constant' control'of the magnet, or coil C, and

incapable of performing 1 fundamental pe-. -r1od c, or so called harmonic vlbratlons.

Such vibrations, if permitted, would be fatal to correct reproduction j of (telephonic voice currents. Q v

A'large machine screw Eoit', iron passes through the'screw hole F'to serve as a shunt tor-[the -magnetic flux and reduce the magnetic attraction on the armature A'when such attraction is in excess of that needed to set -upa properly proportioned initial field for the electro-magnetand sensitize the armature. This regulation is secured by 1 moving the-pointof the screw E toward thehead ofthe iron screw 9' until the initial pull upon the armature A'is reduced; to an amount which permits the electro-magnetic, variations to act with a maximum value upon the armature. Theiaction of the polarized armature A is to increase the efiects of netic circuit is i proved bysaid arrangethe armature, marked at These polar extremities are extensions of thefl southand north poles respectively'of thelpermanent magnet Uand have a normal inutual "at-- traction in proportion tothedehsity of the magnetic flux. magnet coil 0, if of a sign toreinforc'e the permanent flux, will produc'e f'a; forward movement of the armature ,A, said imovement being augmented by the 1 mutual attraction of the polar extremities, and by the released forward tension ofthetohguea. The forward movement of theelectrode c and its momentum due to its inertia will aid in varying the resistance at thepoint or points of contact-betweenjithe platinum and carbon electrodes. A-current in the coil C if of a sign opposing the permanent flux, will, if the permanent flu)": is; roperly' proportioned, cause not: only a wea ening of the normal attraction, but" an additional effect of repulsion between the polar extensions 5 and n, resulting in tin-opposite movement of the armature, which? is-an augmented eliect or increase, of the nsualQretract-ion; The platinum front.electrodei'fe is preferred in this instrument to onset carbon, because it ,instances of use both electrodes -should beof ceiving coil C is associated with the circuit. by means of the-bindi'ng posts V .Vi v

In Fig. 2, which illustrates-the secondarycurrentwork', fthe base B is of insulating material and carries. the repeater instrument which is covered by the glass cover or case G The electro-magnetic receiving supported by brackets D D and the ter minals of the coil are connected with the be wound with fairly coarse magnet wire it placed in the primary circuit, with the transmitter and battery of the receiving repeater. It said coil is used in a circuit secondary to such primary circuit, with an induction coil interposed between them, the winding should be of sma-ller'magnet wire and be in accordance with the secondary winding of the induction coil. I prefer to separate the local circuit connecting the primary and secondary'rep'eaters, asindicated above, and illustrated in Fig. 3, as the strong polarizing effectfof the battery is then avoided in the secondary repeater, As illustrated in Fig. "2xthis repeater-has nopermanent magnet, or

the usual attraction and withdrawal. of the armature by the electip-magnet.-[The ,mag;

ment because the magnetic'fiux ,p'ath afore said is almost closed, the only gap being that between the end ofthe pole markedI-s and can be of small size and weight, and in some platinum or other suitable metal. The re-- 1 05 or transmitting instrument for theic'heavy screw binding posts V V This coil should.

Awnrieiit inthe electrovcoil O and its polar extremities K, K are coil, for polarizing or creating an initial field for sensitization. The sensitization utilized is the magnet flux of the polarized armature A set up by the permanent mag- 5' net U and the ma netic flux is conducted from the N pole of the magnet U to the armature by the small flexible steel tongue a which is secured; to the pole .of the ma net and tothe armature in a suitable slot n J-each. The armature is prevented from:

making contact with or sticking to the polar extremities K K of the electro-magnet 0 by small copfper points P P embedded in aces.

Said instrument may be-constructedwith such a magnet, but I prefer, the electro-magnet; which is here illustrated, as it better avoids undue stress upon the mica transmitter diaphragm a and leaves the latter in a more sensitive state. The armature, instead of being mounted upon, or directly connected with, the transmitter diaphragm (1 as is usual, is, because of its distance from the armature, connected with said diaphragm mechanically by means of the slender and light arm a Said arm a is at-- tached to the armature by screw threads and also to the diaphragm. The front electrode button 6 is fastened in electrical connection to its metal back 6 placed upon the rear of thediaphragm; Anut c is placed upon the front of" the diaphragm and the arm a is,

screwed through them, the nut 6 serving,

when set tightly, to hold the parts firmly to the diaphragm. The transmitterTismounte ed, by means of the screws 6 6 upon the bracket or pedestal D ,'which may he slidable upon the base B and fastened to same by the screw (Z The rear electrode 0 of carbon is electrically connectedgto the rear wall of the granular carbon-containing chamber 0 The diaphragm is tightly clamped to the transmitter casing by the threaded ring 7, and-the annular space be- 55. tween the electrodes is nearly filled with carbon granules. The front electrode 6 is connected by a small copper wire with the binding post M and the connection to the rear electrode is through the bracket sup"- I port D- to the binding post M The alternating telephonic currents cause the polarity of the electro-magnet to correspondingly change, and the alternating polar effects in the poles marked 8 and a cause 66 the polarized armature A to oscillate or move. between the. poles in practical syn-' 'chronism' therewith. Each movement of the vantage of this polarized armature arrangement lies. in theiimproved control of the armature by the attra'ctio'n and repulsion effects thereon. The armature and its connecting arnrto the transmitter are elastically supported by the steel tongue ca -and the imtial stress upon the diaphragm is that due I to the mild attraction of the polarized arma-. 3E0- ture to the pole of opposite sign. The transmitter is thus in a very sensitive state and responds .easily and effectually. A- telephonic 'impulse'acting through the electr c-'- magnet to increase the attraction of the ar mature toward the pole it normally seeks-- the pole of opposite. sign,-'also creates a repulsive effect between the armature and the other pole, thereby augmenting the action.

This arrangement results in a greater move 0 ment than were the diaphragm under considerable stress by a permanent magnet, as is usual in the ordinary magneto-electric receivers and similar receivers in repeaters;

hence, the transmitter receives a correspondingly increased 2 vibration. A telephonic impulse of the opposite sign produces an increased effect by a corresponding cooperation between the magnets, in the opposite direction. That is, the actions are the same but opposite in effect, and said increased effect is owing to the tendency of the diaphragm toresume its normal position when relieved of the initial stress.

Fig. 3 diagrammatically illustrates the arrangement of the apparatus and its. se-' quence of operations from the reception of a telephonic impulse from the incoming line to its retransmission to the outgoing line, after having been twice reproduced and stepped up in volume. The primary or receiving repeater in this view comprises the receiver, transmitter, battery,finduction coil. and circuit connections to the left of the. dotted line.. The secondary or transmitting repeater comprises the corresponding apparatus and circuits to the right of the dotted line. The incoming line circuit L and outgoing line circuit L terminals shown represent the c'onnectionsrespectively to the inductive local repeater circuit and the main line circuit shown more fully in Fig. 4:. The operations involved in transmitting in one direction with this half or one side of the repeater arrangement is as followsiWeak '125 telephonic impulses from line L actuate the first receiving repeater-R, which reproduces the impulses, and, as before stated, with in creased power, through the primary local circuit P indnctively by means of the inprimary I into line L through the line induction'coil wire W, andfoutward wire W Thec'ur strength of the currents from the line re- 'Cljl'lillli from repeater R and its primaryv rent flows are as follows: from line L line wire W 'to'theleft and through the secauction coil I into the secondary local circuit LC where the impulses actuate the transmitting repeater R which, due to-the peater, is enabled tore-repeat the original impulses with much greater power and accuracy than would a repeater operated directly by the original impulses and adapted to actuate a high power or granular transmitter varying a strong local battery, as has heretofore beenthe practice. .The repeated local circuit I are directly induced throu'gl'i the line induction coil 1 intothe outgoing li'ne L whence they are transmitted toward the terminating station.

'In Fig. 4 is illustrated the method of utilizing my double repeater apparatus to secure repeater service both ways, or reciprocally, over a repeater lino circuit. in this arrangement two double repeaters are necessary in order 'to secure unidirectional reciprocal retransmission. The arrangement shown is a'combinatiou of the presentinveiition with my patented circuit system hereinbeforc referred to, in which retransmission is secured with no interference due to reaction effects in the apparatus or sys tem, and full transmitting efliciencyis had in eachdirection from' each repeating transmitter. i J i The designating marks R and R for the receiving repeater and the transmitting re-v peater respectively, shown in Fig. 3, will serve to identify them in this view as the repeaters operating to repeat from line L to line L, as explained. The arrows indicate the current flows in-both the local and secondarycircuits and accord with the effects set up when-a given or'single impulse is received from line L and which is repeated into line L". Tracing the circuit, the curondary winding of line induction coil I to line wire W These flows set up currents in the receiver local circuit B, the resulting current flow corresponding to the arrows to energize repeater receiver R The similarly set up currents in the primary circuit P cooperate through the auxiliary induction coil C to energize the receiver. The actuation of the repeater R induces currents from its primary local circuit P through induction coil 1 into the secondary local circuit L,C*,resulting in the actuation of the secondary repeater E. This latter repeater causes the local battery LB in circuit P to induce strong currents I The flow of the current in' the primarycircuit, as shown'by the arrows,'induces a current in the linew'hich 'iowszinward 1n current in the local circuit B of repeater R, which would energize and actuate that repeater and cause'it to react and become noisy, were it not that the induced current in auxiliary induction coil C from the same primary circuit is made to'balance and oppose the other current in local circuit 13, as will be understood from the-arrows associated with that circuit. As tothe receiving side, it will be remembered that the local current fiows in local circuitB' c0- operated 'to energize the repeater, while in this case, on the transmitting side they are in opposition to prevent energizing the repeater R. The cycle of operations is reversed in the apparatus when the transmission is from the line L 't'o the line L This application for patent shows and describes but one general form of my invention, but it is obvious that those skilled in the art to which it' appertains will be enabled to Vary or change the details of the circuits and the apparatus without departure from the spirit and'scope'of the invention.

I am aware that attempts have been made to secure retransmission of reinforced telephone currents by the use of a pair of relays, one serving in a secondary capacity to the other, but so far asI amaware, such attempts have not been successful and have not gone into practical or commercial operation. The prime requisites of a repeater of this character is a primary relay device nicely proportioned to the weak currents that are available for its operation, correspondingly proportioned members in the secondary relay device for its available currents, a properly proportioned battery supply for each, and an adjustment in the transmitter for each, which permits the normal 105 microphonic effect, and avoids undue pressures -or distortions in the resulting currentsat any stage of the operation.

What I claim as new and desire to secure by" Letters Patent, is p "l. The combination in a telephone repeater,"of two repeaters, each including a pair, 'at' each repeater station, each pair adapted to repeat in a direction opposite to the 'other, each pair comprising a compound 115 telephone repeater composed of a: receiving or primary-relay 'and a transmitting orseco'n'dary-relay'; the primary relays conslstmg adjusted to"'exert merely a"normal microphonic pressure between its contacts of electrodes; the second'ar -relays being sensitive andadapted to. increase andv uniformly magnij currents received by them; a primarylc rcu-iti including a battery,'in circuit 139 with the microphone of each primary-relay, said primary circuits being associated inductively with a respective secondary local circuit in which the receiver of the secondary-relay is connected, the microphones of the secondary relays being adjusted to exert merely. a normal inicroplionic pressure hetween their contacts or electrodes and each microphone having a primary circuit, including a battery, associated inductively-with its respective out-going line.

2. The combination in, a telephone repeater, of two repeaters, each including a pair, at each repeater station each pair ada ted to repeat in a direction opposite to t e other, each pair comprising a compound telephone repeater composed of a receiving or primary relay and a transmitting oi" secondary-relay; the primary relays consisting ofa sensitive receiving telephone and transmitting microphone without a diaphragm and a non diaphragmatic magnetic armature as the vibratoryactuating member,-

the receiving I telephones being associated with the incom ng line circu t, and each microphone adjusted to exert-merely :1 normal microphonic pressure .between its contacts or electrodes; the secondary-relays being sensitive and adapted to increase and uniformly magnify currents received by them; a primary circuit, including a battery, in circuit'with the microphone of each primary-relay, saidprimary circuits being associated inductive y with a respectivesecondary local circuit in which the receiver of the secondary relay is connected, the microphones of the secondary relays being adusted to exertinerel a normal microphonic pressure between their contacts or electrodes, and each microphone having a primary circuit including a battery associated inductively with its respective out-going'line, and

' circuit means and associated inductive means for preventing self-action of. the"repeaters,

3. The combination in a telephone repeater of two repeaters each including a pair at each repeater station, each pair adapted to repeat in a direction opposite 'to the other, each pair comprising a com pound telephone repeater composed of a re-' ceiving or primary-relay and a transmitting or secondary-relay the primary relays consisting of a sensitive receiving telephone and transmitting microphone without a diaphragm and a non-diaphragmatic magnetic armature as the vibratory actuating member, the receiving telephone being associated inductively with the incoming line circuit, and each microphone adjusted to exert merely a normal microphonic pressure between its contacts or electrodes; the secondary relays being sensitive and adapted to increase and ,uniforinly magnify currents received by th' .n'g, a primary circuit, including. a battery',in circuit with the microphone of each priniary relay, saidpriniary. circuits being associated inductively with a respec tive secondary local circuit in which the receiver of the secondary-relay is connected, the microphones of the secondary relays being adjusted to exert merely a normal inicrophonic pressure between their contacts or electrodes and each microphone having a primary circuit, including a battery, associated inductively with its, respective out-going line and circuit means and associated inductive means for preventing self-action of the repeater.

4. In a telephone repeater, the combination of a repeater-circuit adapted to recip-* rocal retransmission with means therein for balancing the circuit against reaction of the repeater, a relay comprising a receiver. and

a transmitter in repeater relation and having as its actuating vibratory element or armature a freely oscillatory tongue or reed-like regulable vibrator for electro-mechanically associating the receiver with the transmitter, I and dominating means. for

damping said tongue, substantially as described.

5. In a telephone repeater, the combination of a repeater-circuit adapted to reciprocalretransi'nission with means therein for balancing the circuit against reaction of the repeater, a relay comprising a receiver and a transmitter in repeater relation and.

:winding connected in circuit with the in- Ward line, said relay having no diaphragm but having a vibratory armature non-diaphragmatic in form, the microphone of said relay having a normal adjustment, a primary circuit for said microphone, including a battery and the primary of an induction coil, a neutralizing local circuit-for said first relay to prevent reaction by repeated currents; a secondary relay with ts winding. connected in a local secondary circuit, sald local secondary circuit also including .the

secondary .winding of the said in'ductioncoil, the microphone of the secondary relay having a normal adjustment, a primary circuit in which'said secondary relay microphone is "connected with a battery and the primary'of the second induction coil,a secondary winding for said second induction coil with which the outward line is in citcuit'ysubstantially'as' described; I

7 In a compound reciprocating telephone repeater comprising two pairs of. relaysfor stepping-up the tranemission' and wherein the relays formingeach pair-are connected tgether by means of a local primary. and a local secondary circuit, said pairs being'arranged electrically opposed for ireclproeal means, both means being Within 1dca1.eir- 

